ISSN:
1573-4919
Keywords:
peroxynitrite
;
nitrotyrosine
;
denitration-enzyme/nitratase
;
glutathione S-transferase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract Putative ‘protein nitratases’, which catalyze denitration of peroxynitrite (PN)-treated proteins, were detected in the homogenate/crude extract of rat brains and hearts. Nitratase activity was monitored by the decreased intensity of nitrotyrosine immunoreactive-bands in Western blot and increased nitrate level in dialysate of incubation mixture, which contained homogenate/crude extract, protease inhibitors and a PN-treated substrate, such as treated histone (III-S), BSA or invertase. Enhanced activity of nitratases was noted by preincubating crude extract with Ca2+. In addition, at least two types of nitratases may occur: type I, reductant-dependent, and type II, reductant- independent. Furthermore, upon denitration, the activity of PN-treated invertase increased to the same activity level of the untreated invertase. The overall reaction catalyzed by nitratases for denitration of nitrotyrosine residues in protein could be as follows: Protein-Tyr-NO_2 + H2O → Protein-Tyr-H + H+ + NO3 −. The nitration/denitration of protein-tyrosine may be crucial in regulating signal transduction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007024126947
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